Most patients with a nondisplaced or adequately reduced DRF can be treated nonoperatively in a cast with excellent functional results, as long as no secondary displacement occurs during follow up. Nonetheless, the optimal nonoperative treatment strategy is still a matter of debate, as no level I evidence existed at the start of this thesis. The purpose of this thesis is to investigate the optimal treatment strategy of nonoperatively treated DRFs and to answer the following questions: • What is the status praesens of nonoperatively treated patients with DRFs? • What is the optimal casting period in nonoperatively treated DRFs? • What outcome might be expected in the treatment of children and elderly with DRFs? • What future research concerning the nonoperative treatment of DRFs is required? This thesis produces new insights in the nonoperative treatment strategy of DRFs. The studies support a change for daily practice towards a shorter period of immobilisation for both non- or minimally displaced and displaced and adequately reduced DRFs. The studies have led to an adjustment of the Dutch guidelines on the nonoperative treatment of non- or minimally displaced DRFs. The advised duration of cast immobilisation has been changed into three weeks for non- or minimally displaced DRF and four weeks for displaced and adequately reduced DRFs. In this thesis, suggestions for the treatment of DRFs in children and octogenarians were presented. Furthermore, recommendations for future research have been done, which will eventually safely minimalise the nonoperative treatment of DRFs to the maximum.